Emit warnings during interpreter execution to stderr.
Some functionality required to be compliant with ruby/spec is deprecated or
invalid behavior and ruby/spec expects a warning to be emitted to
Warning module from the standard library.
Concrete error type for errors encountered when outputting warnings.
Emit a warning message using
This method appends newlines to message if necessary.
Interpreters should issue warnings by calling the
warn method on the
If an exception is raised on the interpreter, then an error is returned.